Dentists' practice activity in Australia: 1983-84 to 1998-99 presents findings on the activity of dentists in private general practice from The Longitudinal Study of Dentists' Practice Activity. Data for this study, based on a random sample of dentists, have been collected in 1983-84, 1988-89, 1993-94 and 1998-99. Trends in practice activity and service provision are presented over the 15-year study period and patterns of service provision in 1998-99 are presented for the main areas of service, and the main diagnoses or conditions. The findings show that both practice patterns of dentists and the content of the services provided have changed over time, consistent with popular trends, towards improved oral health and maintenance of natural dentitions.